Crank grinder



Nov. 3o, 1943.

H. AGOOD 2,335,241

CRANK GRINDER Filed July 29, 1941 Summer /A @vez '9. Gaap Patented Nov. 30, 1943 CRANK GRINDER Harper A. Good, Waynesboro, Pa., assignor to Landis Tool Company, Waynesboro, Pa.

Application July 29, 1941, Serial No. 404,564

4 Claims. (Cl. 51-237) This invention relates to crank grinding machines, particularly to the means for rotating the work.

In grinding or turning crankshafts, it is desirable that the work be driven from both ends in order to avoid excessive twisting of the crank. It is also desirable that the turning force at both ends should be substantially the same.

On crank grinding machines having the entire work drive mechanism mounted on the work table, a motor at one end drives thru a long shaft to both heads. Because of the distance to the farther head, the shaft is subject to torsional deflection and the drive to the head at that end may not carry its full load. By driving from the center of the shaft the deflection will be reduced and will also be divided equally between the two heads. A sprocket at the center of the shaft with means for driving same is obviously out of the question. In the past, crank heads have been driven from a mechanism located in the bed. The only way the drive could be located midway between the heads was to traverse the wheel instead of the work. If the work was traversed it was nesessary to have sliding sprocket or pulley, in which case the sprocket moved along the shaft instead of remaining in the center.

It is therefore an object of this invention to provide means for rotating a crankshaft Wh'ich will apply substantially equal forces at both ends of said crank.,

A further object is to provide such a drive from a motor located at one end of the drive shaft.

In the drawing,

Figure 1 is a partial plan view of the upper portion of a crank grinder.

Figure 2 is the device for effecting a driving connection in the work drive mechanism.

Figure 3 is an end elevation of the device of Figure 2.

In the drawing, numerals I and II are crank heads for rotatably supporting a crank shaft I2. A tubular member I3 is rotatably supported in each' of said heads. Sprockets I5 and I6 are mounted on said tube in each of said heads. Said sprockets are connected to sprockets not shown on the work spindles thru chains I'I and I8 respectively. Said heads are mounted on a work table I9 which in turn is slidably mounted on a bed (not shown).

A shaft 20 is inserted in tube I3 to substantially the midpoint thereof, the inner end of said 5-5 shaft is hollowed and split to form a plurality of expanding jaws 25. The means for expanding said jaws consists of a tapered member 25 having a threaded portion 21 at one end for insertion into a threaded bore 28 in said shaft.

Th'e outer end of said shaft is operatively connected thru any suitable medium to a motor 35i.

It is believed unnecessary to describe the operation of my device since this should be obvious from the above description.

I claim:

1. In a metal working machine, a pair of heads for rotatably supporting a work piece, driving means for said heads including a hollow shaft, driving connections from said shaft to each' of said heads, means for rotating said hollow shaft including a second shaft inserted in one end of said hollow shaft and having means for operably engaging said hollow shaft at substantially the mid-point thereof, and driving means for rotating said second shaft.

2. In a metal working machine, a pair of heads for rotatably supporting a work piece, driving means for said heads including a hollow shaft, driving connections from said shaft to each of said heads, means for rotating said hollow shaft including a second shaft inserted in one end of said hollow shaft and having an expanding collet for operably engaging said hollow shaft at substantially the mid-point thereof, and driving means for rotating said second shaft.

3.`In a metal working machine, a pair of heads forv rotatably supporting a work piece, driving means for said heads including a hollow shaft, driving connections from said shaft to each of said heads, means for rotating said hollow shaft including a motor, at one end thereof and connections from said motor to the inside of said shaft at a point substantially midway between said heads.

4. In a metal working machine, a pair of heads for rotatably supporting a work piece, driving means for said heads including a sh'aft, driving connections from said shaft to each of said heads, means for rotating said shaft including a motor at one end thereof, and connections from said motor to said shaft ata point substantially midway between said heads including a second shaft, one end of which is connected to said motor, the other end to the inside of said first shaft.

HARPER A. GOOD. 

